Combined grinding and lapping disc having flat working surfaces



June 1956 J. A. G. SCHUHMANN COMBINED GRINDING AND LAPPING DISC HAVINGFLAT WORKING SURFACES Filed May 28, 1952 COMBINED GRINDING AND LAPPINGDISC HAVING FLAT WORKING SURFACES Julius August Georg Schuhmann,Schwabach, Germany, assignor to Job. Urbanek & Co., Werk Nurnherg,Nurnberg, Germany Application May 28, 1952, Serial No. 290,412 Claimspriority, application Germany March 18, 1950 Public Law 619, August 23,1954 Patent expires March 18, 1970 10 Claims. (Cl. 51'--209) Forgrinding and lapping, in most cases grinding discs having differentcoatings are employed one after the other, Thus for instance thegrinding of Widia turning tools is normally effected by means of siliconcarbide grinding discs, whereas fine grinding and finishing grinding isin most cases effected by means of discs covered with diamond powder.Then, grinding tools provided with diamond dust bonded by means of asynthetic substance are used for lapping.

The object of the invention is in all such cases to enable the grindingand/or lapping work, for which two or more operations with grindingtools having suitable coatings have been necessary heretofore, to beeffected in a single operation. The invention achieves this object byproviding springs acting between the rings and tending to push theworking surface of one ring in front of the working surface of the otherring, and a locking de' vice which in its locking position prevents thesprings from acting.

A further feature of the invention is the arrangement of a sealing meansbetween the rings.

Several embodiments of the invention, chosen by way of example, areillustrated in the accompanying drawings, in which:

Figure 1 is an axial section through a grinding and lapping discconsisting of two concentric rings, the inner ring being pressed againstthe outer ring by a pressure spring.

Figure 2 is a modification of the embodiment according to Figure 1.

Figure 3 is a further modification of the embodiment according to Figure1.

In Figure 1, the outer ring 1 is provided with the coating 2 of diamondpowder or the like. This ring is made in the form of a cup and its hub 3is provided with a tubular extension 4. The inner ring 5 carrying adiamond coating 6 suitable for lapping is also made in the form of acup. A sealing means 7 is arranged between the rings 1 and 5. The innerring has a hub-like part 8 which is slid over the tubular part 4. It issubjected to the action of pressure springs 9 which tend to force itinto a position in front of the ring 1. Between the hub-like part 8 andthe tubular part 4 is arranged an adjusting ring 10 subjected to theaction of pressure springs 11. These springs press the ring 10 against astop ring 12 which prevents it from being pushed out over the tubularextension. The adjusting ring 10 is provided with notches 13 in whichround heads of locking pins or detents 14 engage, these locking pinsbeing arranged radially displaceably on the hub-like part 8 of the innerring 5 and subjected to the action of springs 15. The adjusting ring 10is also provided with a stop ring 16 which prevents the inner ring 5from falling out. Pressure on the adjusting ring 10 causes it to yieldrearwardly against the action of the springs 11. The notch 13 and thehead of the locking pin 14 are so shaped that the locking pin 14 ispushed back by this movement of the adjusting ring,

- ite States Patent O 2,749,684 Patented June 12, 1956 so that the innerring 5 jumps forward under the action of the springs 9 until it bearsagainst the stop ring 16. The inner ring 5 is now somewhat in front ofthe outer ring 1 and is in the working position.

In the embodiment of the invention according to Figure 2, the hub 21 ofthe inner ring 20 slides axially displaceably on the prolongation 22 ofthe hub 23 of the cup-shaped outer ring 24. The inner ring is subjectedto the action of pressure springs 25 and is provided with a cap 26covering the opening of the tubular extension 22. In its central part itcarries a press-button 27 which through an intermediate lever 28 can acton a spring pressed catch lever 29 having a lug 30 engaging in a groove32 of the tubular extension 22. When the catch lever 29 is disengaged bypressure on the press-button 27, the inner ring 20 jumps in front of theouter ring 24 and is thus ready for operation.

In the embodiment of the invention according to Figure 3, the outer ring40 is screwed on to a disc 31 by means of screws. The inner ring 33,subjected to the action of pressure springs 39, is axially displaceablein the outer ring. The axial displacement of the inner ring is limitedby an abutment 34. The disc 31 carries a ring 35 in which there is acruciform slot 36. A pin 37 attached to the ring 33 engages in thisslot. Figure 3 is so drawn as to show the inner ring 33 in its rearrnostposition on the left hand side and in its foremost position on the righthand side. if the inner ring (see left hand half of Figure 3) is turnedthrough a few degrees rela tively to the outer ring, then the upper part33 of the cruciform recess 36 comes into a position above the pin 37, sothat the ring 33 now jumps in front of the outer ring 40 (see righthandhalf of Figure 3). This bayonet like closure enables the inner ring tobe returned to the rearward position by being pressed back and turnedslightly.

It is believed that in view of the foregoing that a further detaileddescription of the operation of the invention is unnecessary. Likewise,it is believed that the advantages of the invention will be readilyapparent.

Having thus fully described the invention, what is claimed to be new anddesired to be secured by Letters Patent is:

1. In a device of the class described, two concentricaL ly arrangedgrinding rings, the one for coarse grinding, the other for fine grindingand lapping, the inner grinding ring being axially displaceable from aposition with its grinding face behind the outer grinding ring to aposition in front of the outer grinding ring, springs for effecting saidaxial displacement, and spring pressed detent means for preventing saidaxial displacement at will.

2. In a device of the class described, two concentrically arrangedgrinding rings, the one for coarse grinding, the other for fine grindingand lapping, one of the grinding rings being axially movable from aposition with its grinding surface behind the grinding surface of theother grinding ring to a position with its grinding surface in front ofthe other grinding rings, springs for effecting said axial displacement,one of the rings having an annular recess therein, and a spring loadedand radially movable locking piece carried by the other grinding ringengaging with said annular recess when, against the action of saidsprings, the one grinding ring is pushed back hehind the grindingsurface of the other grinding ring.

3. In a device of the class described, two concentrically arrangedgrinding rings, the one for coarse grinding, the other for fine grindingand lapping, one of the grinding rings being axially movable from aposition with its grinding surface behind the grinding surface of theother grinding ring to a position with its grinding surface in front ofthe other grinding ring, springs for effecting said axial displacement,one grinding ring being provided with an annular recess, and a springloaded and radially movable locking piece carried by the other grindingring engaging said said annular recess when, against the action of saidsprings, the one grinding ring is pushed back behind the grindingsurface of the other grinding ring, and a concentrically located piecefor disengaging said locking piece from said recess.

4. In a device of the class described, two concentrically arrangedgrinding rings, the first for coarse grinding, the second for finegrinding and lapping, said second grinding ring being axially movable infront of the other grinding ring, springs for elfecting said axialdisplacement, said first grinding ring having an annular recess therein,and a spring loaded and radially movable locking piece on the secondgrinding ring engaging with said annular recess when, against the actionof said springs, the second grinding ring is pushed back behind thegrinding surface of the first grinding ring, and a concentricallylocated and axially movable piece for disengaging said locking piecefrom said recess.

5. In a device of the class described, two concentrically arrangedgrinding rings, the one for coarse grinding, the other for fine grindingand lapping, the outer grinding ring having a hub on the outside ofwhich slides axially the hub of the inner grinding ring, springs betweenthe inner and the outer grinding ring forcing the inner grinding ring infront of the outer grinding ring, the inside of the hub of the outergrinding ring being provided with an annular recess, a cap centricallyfastened on the hub of the inner grinding ring, catch levers pivoted onthe inside of said cap, springs forcing said catch levers to engage withsaid annular recess, and a button in the middle of said cap to disengagesaid catch levers from said recess by pressing it inward.

6. In a device of the class described, two concentric grinding rings forsuccessive use in a grinding operation, the inner of the two rings beingmovable relatively to the outer ring, springs between said rings tonormally hold the inner ring in a position with its face forward of theface of the outer ring, said inner ring being movable against springpressure to a position with its face behind the face of the outer ring,and detent means to hold the inner ring in such position.

7. In a device of the class described, two concentric grinding rings forsuccessive use in a grinding operation,

the inner of said rings being movable axially from a position with itsface retracted within the outer ring to a position with its facepresented beyond the face of the outer ring, detent means acting betweensaid inner and outer rings and operable to hold the inner ring inretracted position and manually means operable to release said innerring from said detent.

8. The device of claim 7, in which an annular sealing element isprovided between the outer periphery of the inner ring and the innerperiphery of the outer ring to exclude abrasive material from the spacebetween said rings.

9. In a device of the class described, an inner abrasive ring and anouter abrasive ring concentrically mounted for successive use in agrinding operation, and manual means by which relative axial movementbetween the two rings may be effected to selectively present either theabrading surface of the inner ring or the abrading surface of the outerring to a work piece, said manual means comprising spring means tonormally force said inner abrasive ring axially forward with respect tosaid outer abra sive ring and bayonet slot latch means to secure theinner ring in position with its face axially inward of the face of theouter ring.

10. In a device of the class described, an inner abrasive ring and anouter abrasive ring, concentrically mounted for successive use in agrinding operation, and manual means by which relative axial movementbetween the two rings may be effected to selectively present either theabrading surface of the inner ring or the abrading surface of the outerring to a work piece, said manual means comprising spring means tonormally force said inner abrasive ring axially forward with respect tosaid outer abrasive ring, radial spring pressed detent means to holdsaid inner abrasive ring against said spring means in position with itsface axially behind said outer abrasive ring and means to release saiddetent means.

References Cited in the file of this patent UNITED STATES PATENTS432,212 Nelson July 15, 1890 FOREIGN PATENTS 199,312 Germany Nov. 10,1907 247,293 Switzerland Nov. 17, 1947 442,246 Germany Mar. 23, 1927

